This invention relates generally to power-operated cross-arm and single arm window regulators for raising and lowering vehicle windows and, more particularly, to a device for cushioning movement of windows by such regulators to raised position.
Single arm and cross-arm window regulators have been in widespread use in vehicles for decades. Both comprise welded metal assemblies in which one end of a pivotable lift arm mounts a gear sector which is driven by a pinion. The other end of the lift arm mounts a roller or other slider which slides in a glass-mounted channel as the arm is raised and lowered to raise and lower the window. The cross-arm regulator adds a force-stabilizing equalizer arm pivoted to the lift arm which mounts a slider on both ends --one slidable in the window channel and the other slidable in a fixed channel. The equalizer arm scissors on the lift arm to equalize the forces tending to tilt a window as it is raised and lowered by the lift arm.
The lift arm is driven up and down by a driving pinion which engages a sector mounted on the inner end of the lift arm. In years past, the drive pinion of these regulators has been operated by a manual crank. Gradually, these "manual windows" have been displaced by "power windows" in an increasing variety of vehicles. These power windows replace the manual crank with an electric torque motor-powered operator to drive the pinion. Currently, these drive motors are operated by manual switches located in the passenger compartment.
Both the raised and lowered positions for the windows can be defined in many ways. In one power window application, the window raised position is defined by engagement of a stop surface on the sector arm with a cooperating stop surface, such as the drive pinion or the motor housing or other structure. Upon engagement of these stop surfaces, window movement halts. If the manual switch is not released when the window reaches raised position, the motor will continue to run until it overloads and stalls out.
A problem has been encountered with this power window arrangement. As the window nears raised position, it engages a window seal, which provides some varying resistance to completion of window movement to fully closed position. The resistance encountered can vary greatly, depending on vehicle build tolerances and vehicle seal type, which varies for framed or frameless windows. If sufficient resistance is encountered, the drive motor will stall out prematurely, before the window reaches fully raised position.
The window regulator test specifications established by the vehicle manufacturer will determine the output required of the drive motor. Higher output of the motor produces higher impact forces on the window regulator, especially in the fully up and down window positions. In vehicles where little seal resistance is encountered, the arm stop surface engages the operator stop surface with a significant impact force. In certain cases, this repeated and unrestrained impact can have a significant effect on the structural integrity of the window regulator and can even result in breakage of welds and component parts.
It would be desirable to provide some means to cushion the final movement of the window to raised position to reduce the impact force imposed on the component parts of the window regulator.
It would also be desirable to provide resilient cushioning means located in the window lift channel which are increasingly stressed by movement of the slider to window raised position.